The research centers on the processing of visual information from object-like patterns. We have found that we can dramatically enhance human observers' performance in the simple task of identifying barely perceptible, briefly-flashed line segments. The enhanced performance results from adding auxiliary lines which combine with the target line to yield perceptions of unified, three-dimensional objects. We have called our facilitatory effects "object-superiority" and "object-line" effects (by analogy with the much studied word-superiority and word letter effects--superior detection of a letter when flashed as part of a pronounceable word). These object-superiority and object-line effects may help identify how the visual system uses global factors to build its representations of objects. The experiments can tell us which factors are important, at what stages they enter into visual processing, and how they interact. By designing context patterns which vary in key structural characteristics such as connectedness, perceived depth, apparent solidity and geometric distortion, we can identify a variety of spatial factors that may contribute to these effects. By presenting the target lines at various times before and after presentation of the auxiliary context lines (time-course of accuracy-metacontrast), we can ascertain when and where in the perceptual process certain critical operations are taking place. These operations can then be further pinned down by measuring "two-flash" thresholds, reaction time, "temporal integration" times, and flicker.